1. Field of the Invention
The present invention relates to a vibration suppressing apparatus for a structure which is capable of suppressing the vibration of a structure caused by an earthquake, wind pressure, or the like.
2. Description of the Related Art
In the field of structural design, a vibration suppressing apparatus for suppressing the vibration of a structure with lever-weight mechanism has been proposed so as to improve dynamic properties of a conventional earthquake-proofing structure Japanese Patent Application Laid-Open No. 300540/1990).
This vibration suppressing apparatus is arranged such that a weight is pivotally attached to a distal end of a differential lever disposed in an arbitrary story of a structure, and the motion of the weight due to vibrations caused by an earthquake or the like is amplified by a lever ratio, thereby producing a large inertial force. The relative horizontal displacement of the main structure is offset by this inertial force, because the amplified inertial force can greatly consume kinetic energy caused by the earthquake of the like.
With the conventional vibration suppressing apparatuses, however, since the vibration suppressing direction is limited to one horizontal direction only in order to suppress the vibrations occurring in two horizontal directions due to the earthquake or the like, it has been necessary to provide two separate vibration suppressing apparatuses in the two horizontal directions (in the directions of the X and Y-axes). In addition, since the differential lever generally comprises a short arm, in length so as to give high stiffness it has been necessary to provide a pantograph or the like for preventing the arcuate motion of the weight attached to the distal end of the differential lever.
For this reason, the conventional vibration suppressing apparatuses experienced the drawbacks that the mechanism is complicated and the installation space becomes large.